Mammalian visual cortices contain multiple superimposed maps for
different stimulus attributes, such as receptive field position, edge
orientation, spatial frequency, direction of motion and eye preference. I
will review some of the experimental evidence for the existence of these
maps as well as the evidence for gradient relationships and other types of
structural link between them. I will compare these data with modelling
results obtained using Kohonen's Self-Organising Feature Map algorithm
which implements a competitive learning rule. I will discuss the extent to
which the maps produced by this model, and a variant of it, are able to
reproduce the experimentally observed properties of individual maps, as
well as the gradient relationships between different maps.